The present invention relates to a method and apparatus for treating blood for the removal of insoluble fat therefrom, preferably for re-transfusion (autotransfusion) of the blood with the insoluble fat removed therefrom, back into the patient. This invention is directed to trauma, pre-operative, post-operative and intra-operative blood treatment.
Between intra-operative and post-operative blood re-use, post-operative blood collection for re-use has had increased medical interest, because the blood is generally freer of debris, contaminants and the like.
Re-use of blood has taken on increased interest with concern for possible contamination of a patient being transfused with blood other than the patient's own, during or after various types of surgery.
Accordingly, for example, during various operations of various kinds, be they emergency operations, chest, abdominal or limb operations, it is becoming increasingly commonplace to withdraw the blood from the patient, and to endeavor to collect that blood and return it reasonably promptly to the patient via intravenous techniques, generally after filtering clots or other debris, such as bone chips and the like therefrom, such as in accordance with the above-mentioned applications.
In accordance with the present invention, a number of observations have been made, and will be explained hereinafter, in connection with various orthopedic procedures, such as involve long bone fractures or other treatment procedures, hip replacements, knee replacement and the like, but it will be understood that fat removal in accordance with this invention may be desirable on the occasion of any type of surgery, trauma or any type of blood treatment. Consequently, references herein to orthopedic treatment and/or procedures will be considered to be by way of example only, and not limitations on the scope of the present invention.
One of the goals of the invention will therefore be the removal of free fats or lipids that are observed on the surface of blood collected post-operatively in orthopedic procedures, wherein it is intended that the blood be used for direct reinfusion. It is noted that such free lipids may occur floating on the top surface of blood collected in a container post-operatively, for example, following total joint arthroplasty. Such free lipids can be detected visually, appearing as a clear fluid floating on the top of the remainder of the liquid; namely the blood, sometimes having a clearly defined interface between the blood and the lipid. Sometimes this interface can be further distinguished by slightly agitating the collection reservoir, resulting in a disturbance of the free lipid such that it forms large globules surrounded by blood serum with the blood then settling to allow a clear, undisturbed layer to resurface. This clear layer is essentially the fats that are insoluble in blood.
The sources of insoluble liquid from procedures such as orthopedic procedures in the drainage fluid is the disturbed bone marrow and the surrounding adipose tissue. Such insoluble fats or lipids consist largely of mixed triglycerides.
The presence of the insoluble fats in the blood system, if allowed to be retransfused to the patient, can result in pulmonary fat embolisms in the lungs; occurrences in which fat globules constrict tiny passages in the lungs, limiting the breathing capacity of a patient, and sometimes resulting in death. The cause of the presence of such insoluble fat globules can be from the raining of fat from marrow into circulation as a result of trauma or excess pressure within the bone cavity, or from simply the presence of insoluble fats within the blood of a patient, by reasons of trauma from an accident, a medical procedure, or whatever reason.
Clinically, the syndrome of pulmonary fat embolism can present symptoms such as dyspnea, tachycardia, anxiety, confusion, focal neurologic deficits and coma. Such emboli may be revealed in chest x-rays, and may also be suggested by elevated body temperature.
Consequently, the pulmonary effects of orthopedic free lipid are a primary concern because this blood is administered via peripheral venous access.
In accordance with the present invention, significant amounts of free lipids (or insoluble fats) in the blood may be removed prior to re-transfusion of the blood. For example, it has been noted, in tests, that 93% of such insoluble fats have been removed (with the remainder coming into contact with and adhering to the walls of the vessel in which removal takes place). Thus, the wicking of such free lipids demonstrates the capability to remove large quantities of mixed triglyceride from the blood, to return the blood serum to near normal levels of triglycerides, which would be the soluble triglycerides.